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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .my-h1{
            color: red;
        }
    </style>
</head>
<body>
    <!-- 匈牙利命名法 my-h1 -->
    <!-- 驼峰命名法  myH1 -->
    <h1 class="my-h1">
        我是标题标签
    </h1>

</body>
</html>